1. Field of the Invention
The present invention relates to a nozzle contact device of an injection machine, and particularly relates to nozzle contact device for setting a contact force between a nozzle and a mold to reduce the cost.
2. Description of the Related Art
Within the next few years, the development of various injection methods is adapted to an injection mold machine. However, a contact method between a mold and a nozzle of an injection device does not change substantially. An oil pressure injection machine has an oil pressure cylinder used to produce nozzle contact force. A nozzle contact device of an all-electric injection machine has a motor and a ball screw, and the motor drives the ball screw to produce nozzle contact force. However, the ball screw is expensive and time-consuming to produce, and it is hard to assemble and maintain the ball screw.
FIG; 1 shows. the all-electric nozzle contact machine of prior art according to U.S. Pat. No. 4,676,730. A nozzle contact method of the all-electric nozzle contact machine uses a motor 90 to drive a screw 91 for transforming the rotation action into the straight action, and then drives an injection device 92 to bring nozzle 93 into contact with mold 94. The all-electric nozzle contact machine has an elastic body 95 such as, for example, a disk spring or a compressed spring for holding the nozzle contact force between the nozzle 93 and the mold 94. The motor 90 provides a power of the nozzle contact force between the nozzle 93 and the mold 94.
Hence, the oil pressure cylinder of the oil pressure injection machine is used to produce nozzle contact force. With regard to the all-electric nozzle contact device, the motor drives the ball screw to transform the rotation action into the straight action for producing nozzle contact force. The oil pressure injection machine adjusts pressure for adjusting the pressure of the nozzle contact force. The motor of the all-electric nozzle contact device is driven continuously for compressing or twisting the elastic body to change shape, and then deciding the nozzle contact force according to the change.
Therefore, the injection machine of the prior art does not need accurate control according to the above description. The ball screw does not need to be used in the injection machine, or it will increase the cost for assembling the ball screw.